Trench pump



1935. T. M. RAGSDALE ET AL TRENCH PUMP Filed Feb. 26, 1934 2Sheets-Sheet -l e m M 5 4 Dec. 17, 1935. T RAGSDALE E 2,024,703

TRENCH PUMP Filed Feb. 26, 1934 2 Sheets-Sheet 2 f/Mm'fams Patented Dec.17, 1935 'mENon rum Tom M. Ragsdale and David J. Conant,

. Memphis, Tenn.

Application February 26, 1934, Serial No. 712,915

7 Claims.

This invention relates to vertical centrifugal pumps of the highsuction, self priming type. It particularly relates to a combinationfluid pump and vacuum air pump, vertically spaced apart and directlydriven by a common extended shaft.

The primary object of this invention is to provide means forautomatically priming a fluid pump having an intake through which fluidis raised to the pump by suction. v Other objects are; to provide meansfor maintaining a high vacuum head in a high suction lift pump; toprovide a simple and compact combination fluid and air pump; to providea fluid pump and an air pump spaced vertically thereabove with an airconduit connecting said pumps, and to provide a fluid pump and an airpump spaced thereabove, both pumps being driven by a common hollowshaft, which serves also as the air conduit from the fluid to the airpump. 20 The means by which the foregoing and other objects areaccomplished and the manner of their accomplishment will be fullyunderstood from the following specification on reference to theaccompanying drawings in which:- 25 Fig. 1 is a vertical sectionalelevation of the preferred type of the assembly, the motor and air pumpbeing shown in elevation.

Fig. 2 is an enlarged fragmentary sectional plan, taken as on the lineIIII of Fig. 1, showing a typical form of vacuum pump.

Fig. 3. is a corresponding fragmentary sectional elevation of the samevacuum pump.

Fig. 4 is a vertical elevation of a modified form of the deviceemploying a solid pump shaft and auxiliary air conduit.

Fig. 5 is a sectional plan taken as on the line V-V of Fig. 4.

, Fig. 6 is a fragmentary sectional elevation showing the automaticcontrol valve in the air conduit. g

Referring now to the drawings in which the various parts are indicatedby numerals;

III is the casing of a typical vertical shaft fluid pump of centrifugaltype, I I is the impeller which is mounted on a hollow vertical shaft I2and is driven by an electric motor I3. If desired-the shaft I2 may beenclosed in a sleeve I4.

Secured to the bottom of the casing I0, is a 50 check valve I5, fromwhich depends a suction pipe I6 of desired length. Extending upward fromthe casing is a fluid discharge pipe I'I, substantially concentric withthe shaft I2 and sleeve I4 which discharge pipe terminates in a dis- 55harge head I8. I! is a check valve preventing return flow through thedischarge head. 20 is a stufling box around the shaft I2.

The discharge head I8 supports a frame 2I, which serves as a base forthe motor I3.

Also carried by the frame 2|, is a vacuum 5 pump having a shell 22,through which the shaft I2 passes. The rotor 23, of this pump, ismounted on and turned by the shaft I2. Air inlet to the vacuum pump isupward through the central bore of the shaft. This bore as shown in Fig.3, 10 preferably terminates at the vacuum pump, but in any event isclosed at the upper end of the shaft. 25 are openings from the shaft,leading to a passageway 26 and thence'into the shell 22.

-21 is a discharge opening to the atmosphere.

The bore 24 is provided, adjacent the level of the impeller II, with anannular valve seat 28, against which a ball check 29 is adapted to seat.The ball is retained in the bore, as by lugs 30, and is preferablylighter than the liquid which is to be handled by the centrifugal pump,whereby rise of such liquid will raise the ball against the seat and cutoff flow through the bore of the shaft; such condition however may beestablished by balancing part of the weight of the valve by a spring.

In Figs. 4, 5 and 6 a modification of the device is shown, partscorresponding to those above described being distinguished by the sufilxletter A. In these views the pump shell 22A is disposed ad- 30 jacentbut not around the shaft I2A.

Thus disposed the vacuum pump may be driven as by complementary gears3IA, 32A, mounted respectively on the centrifugal pump shaft I2A and thevacuum pump shaft. The shaft I2A 5 may be solid and communicationbetween the vacuum pump shell and the centrifugal pump casing isestablished by a tube 33A, opening at its upper and lower ends into suchshell and casing respectively. 28A is the ball check-seat, and 29A theball check, in this communicating tube.

It will be understood that, the motor, centrifugal pump and vacuum pumpmay be of conventional and/or usual type and such illustration anddescription thereof, as is introduced, is intended to be typical only ofsuch devices.

It will also be understood that in some cases the ball check may beomitted, this being particularly evident wherethe vacuum pump is spaceda greater distance above the fluid pump than the vacuum lift of suchfluid.

In operation, the pump is set up with the suction pipe I6, or I 6Aextending into the fluid to be raised. Motor I3 is started and thevacuum pump exhausts air from the centrifugal pump casinguntilthefluidrisesinthe casing andis picked up by the pump impeller. At suchtime 1 the fluid rising in the shaft bore 24, ortube "A as the case maybe, rises to the full vacuum lift until the fluid raises the ball checkagainst its seat and cuts of! flow to the vacuum pump. Also duringoperation should air enter the liquid pump and allow the ball check todrop, the vacuum pump will function to remove such air and restore thefluid pump to normal functioning.

. Also' when pumping fluid from a sump, well or basin in which the flowor the supply is limited or restricted, and air will enter with thefluid, or where the suction head of the fluid pump would normally bebroken by admission of air, it is necessary to pump the air out tocontinue operation.

the pump casing when the unit is inoperative and upon operation thecheck valve is closes off the interior of the pump so that the vacuumpump can build up the necessary suction head.

What is claimed is:-

1. In a device of the character described, a centrifugal pump forfluids, having a casing, a suc-' tion intake depending from said casing,a discharge pipe extending upward therefrom, a motor carried by saiddischarge pipe, said motor having a shaft extending downward therefromand carrying the impeller of said pump, a vacuum pump having a casingdisposed around said shaft and having a rotor mounted on said shaft,said shaft having a bore connecting the inlet of the vacuum pump withthe intake of the centrifugal pump andhaving in said bore a valve seat,a valve supported in said bore below said seat, said valve being lighterthan the fluid to be pumped, whereby to be seated by rise of said fluidand prevent flow of fluid to said vacuum pump.

2. In a device of the character described a centrifugal pump for fluids,having a casing, an impeller, a suction intake depending from saidcasing, a discharge'pipe extending upward therefrom, a motor supportedabove said pump, said motor having a shaft extending downward therefromand carrying said impeller, a vacuum pump having a casing around saidshaft andhaving a rotor mounted on said shaft, said shaftshaving a boreconnecting the inlet of the vacuum pump with the intake of thecentrifugal pump and having in said bore a valve seat, a valve supportedin said bore below said seat, said valve being lighter than the fiuld'tobe pumped, whereby to be seated by rise of said fluid and prevent flowof fluid to said vacuum pump.

3. In a device of the character described a centrifugal pump for fluids,a motor spaced above said pump, said motor having a depending shaft,said pump having a casing, an impeller, a suction intakedepending fromsaid casing, a discharge pipe extending upward therefrom substantiallyconcentric with said shaft, and supporting said motor, a vacuum pumphaving a casing disposed 4. In a device of the character described, acentrifugal pump for fluids, having a casing, a suction intake dependingfrom saidcasing, a discharge pipe extending upward therefrom, driv-' ingmeans carried by said discharge pipe, a shaft v extending downward fromsaid driving means and carrying the impeller of said pump, a vacuum pumphaving a casing disposed around said shaft and having a rotor mounted onsaid shaft, said shaft having a bore connecting the inlet of the vacuumpump with the intake of the centrifugal pump, and means for preventingflow of liquid to said vacuum pump.

5. In a device of the character described a cen trifugal pump forliquids, having a casing, an impeller, a suction intake depending fromsaid casing, a discharge pipe extending upward therefrom, driving meanssupported above said pump,

a shaft extending downward from said driving; means and carrying s'aidimpeller, a vacuum pump having a casing around said shaft and having arotor mounted on said shaft, said shaft having a bore connecting theinlet of the vacuumpump with the intake of the centrifugal pump, saidvacuum pump being spaced above said liquid pump a distance in excess ofthe vacuum lift of said liquid, whereby to prevent flow of liquid tosaid vacuum pump.

6. In a device of the character described, a centrifugal pump forliquids, driving means spaced above said pump, a shaft depending fromsaid driving means, said pump having a casing,

an impeller, a suction intake depending from said casing, a dischargepipe extending upward therefrom substantially concentric with saidshaft, and a; supporting said driving means, a vacuum pump having acasing disposed around said shaft and having .a rotor mounted on saidshaft, tubular means connecting the inlet of the vacuum pump with theintake of the centrifugal pump, said vacuum pump being spaced above saidliquid pump a distance in excess 'of the vacuum lift of saidliquid,-whereby to prevent flow of liquid to said vacuum pump.

'7. In a device of the character described, a centrifugal pump forliquids, having a casing, an impeller, a suction intake depending fromsaid casing, a discharge pipe extending upward therefrom, driving meanssupported by said pipe above said pump, a shaft extending downward fromsaid driving means and carrying said impeller, a vacuum pump, means fordriving said vacuum pump, tubular means connecting the inlet of thevacuum pump with the intake of the centrifugal pump, said vacuum pumpbeing spaced above said liquid pump a distance in excess of the vacuumlift of said liquid, whereby to prevent flow of liquid to said vacuumpump.-

TOM M. RAGSDALE. DAVID J. CONANT.

